Safety valve



C. NELSON l Aug. 18, 1936.

SAFETY VALVE Filed March 2l, 1934 4 NVE'NTOR CAR NELsoN i Avvonwzve ValPatented Aug. 18, 1936 SAFETY VALVE Carl Nelson, Eau Claire, Wis.,assignor to National Pressure Cooker Company, Eau Claire, Wis., acorporation of Wisconsin Applica-aon Maren 21, 1934, serial No. '116,611

2.Claims.

lThis invention relates to newland useful improvements in safety valves,generally. and more particularly to valves adapted for use in connectionwith such apparatus as pressure cookers. An object of the invention isto provide a safety valve 'comprising a valve having a spring normallyholding it in engagement .with its seat against the pressure of the uidin said chamber', 'and comprising means whereby the tension in saidspring may be varied to cause the valve to unseat when a predeterminedpressure is reached in said chamber.

Other objects reside in the novel construction of the safety valvewhereby the unseating of the valve thereof may be controlled with amicrometer adjustment to thereby permit the steam or fluid pressurewithin the chamber to escape therefrom very slowly: and. in theprovision ci a combination safety or pop valve and a pressure releasevalve, which is small and compact, is posic tive in operation, and mayreadily be adjusted to control the escape of the steam from thechambergwith which said valve is connected. Other objects of theinvention will appear from the following description and accompanyingdrawing and will be pointed out in the annexed claims. f

In the accompanying drawing there has been disclosed a structuredesigned to carry out the various objects of the invention, but it is tobe .understood that the invention is not conned to the exact featuresshown as various changes may be made within the scope of the claimswhich follow.

In the drawing: Figure 1 is a vertical improved valve showing sition;

Figure 2 is a similar view unseated; and ,L

` Figure 3 is a view showing the device as applied to' an ordinary typeof steam cooker.

In the selected embodiment of the invention here shown, there isillustrated in Figure 3, for 45 purposes of disclosure, a pressurecooker comprising a body portion 2 having a cover 3 secured thereto bysuitable securing means, generally indicated by the numerals 4 and 5,whereby the cover is secured to the body portion in 50 hermeticallysealed relation.

'I'he novel safety valve herein disclosed, is shown comprising a bodyportion 6, preferably cylindrical in cross-section and threaded at itslower end tofreceive a base plug l. The plug I 55 has a reduced threadedextension I adapted to sectional view of my it in normal closedposhowing the valve be received in a threaded socket 9 provided in -asuitable support, such as the cover 3. A uid circulating passage II isprovided in the plug I and terminates at its upper end in a valve seat I2. The passage II establishes communication 6 between the interior ofthecooker body 2 and the interior of the valve casing 6, as will readily beunderstood by reference to Figures 1 and 2.

A suitable valve I3, preferably spherical in form,

is secured to the lower end of a stem I4, the l0 l upper end of which isslidably received in a. guide opening I5 4provided in an `exteriorlythreaded sleeve I6. The sleeve I6 is received in threaded engagementwith the upper end portion of the valve casing 6 and is secured inadjusted 'l5 position therein by such means as a lock screw II. Thesleeve I6 extendsv beyond the upper end oi the valvevcasing 6 and hasmounted thereon,v an annular adjusting nut or member Iii,v axiallyadjustable thereon.

An enlarged head I9 is secured to the upper end of the valve stem Il andoverhangs the upper end of the sleeve I6 whereby it maybeengaged by theadjusting member I8, when the latter is moved upwardly, as shown inFigure 2. Such 25 upward movement of the member-I8 will unset the valveI3 from its seat I2, as will readily be understood by reference toFigure 2. A suitable spring 2| constantly urges the valve I3 intoengagement with its seat. Suitable fluid-circulating passages 22 areprovided in the wall of the valve casing 6 to permit the pressure fluidentering the valve casing to escape therefrom to the atmosphere.

The threaded sleeve I6 is shown provided at 35 its upper end with a slot23, whereby it may be conveniently rotated to relatively adjust it withrespect to the valve casing 6, by such means as a screw driver or othersuitable instrument. Relative vertical movement of the sleeve I6 variesthe tension in the spring 2|. An aperture 24 is shown provided in thehead I9, through which an instrument may also be inserted to relativelyrotate the threaded sleeve I 6.

The. novel valve herein disclosed provides a combination safety andrelease valve. When the adjusting member I8 is in the position shown inFigure 1, the spring 2i normally holds' the valve on its seat to therebynormally interrupt uid flow through the passage II. When the pressure inthe cooker body reaches a predetermined point, determined by theadjustment of the tension of the spring 2|, the valve will unseat tothereby permit the excess steam or pressure to escape 55 from the cookerbody throughvthe valve casing l and the apertures 22, to the atmosphere.

When the valve is used in connection with a steam pressure cooker suchas illustrated in Figure 3, it is often desirable that itbe so adjustedthat the steam is released very slowly from the cooker body. I havefound that when the steam is suddenly or quickly released from thecooker, there is a tendency to draw or extract the juices from thevegetables and vother articles of food which may be contained within thecooker body,

which of course is objectionable. Such -extraction of the juices fromthe food articles in the cooker may be completely eliminated by theemployment of this novel valve, for by its use, the steam may bereleased very slowly from the cooker body before the cover is'releasedtherefrom.

The novel valve herein disclosed is so constructed that by.simplyrotating the member II, the valve may be unseated by a micrometeradjustment whereby the discharging of the steam from the cooker body maybe controlled at will.

The tensionof the spring may also readily be varied by simply looseningthe lock screw Il and relatively rotating the-'threaded sleeve I6 in itssocket, whereby the safety valve may be caused to operate when' apredetermined pressure is reached in the cooker body. The device is verysimple and inexpensive, and combines in one small, compact unit, acombined safety valve and a fluid release valve, which is neat inappearance and simple to operate.

I claim as my invention:

1. A valve structure comprising a body having a valve seat, a valveoperatively associated with 5 the seat and having a stem, a spring forseating the valve, means in threaded engagement with the body andforming a guide for said stem and the valve, means in threadedengagement with 20l the body and forming a guide for said stem andadjustable for varying -the tension on the spring.

means in threaded engagement with the guide and a stop on said stemengageable by said last mentioned means to gradually unseat the valve,A25 said guide having a screw driver slot and said stop having an openingthrough which an instrument can be passed to engage the slot and adjustthe guide to vary the tension on the'spring.

CARL NELSON. 30

